This invention relates to an image forming apparatus into which a cartridge having a built-in memory is inserted, and to a method of controlling the memory.
An image forming apparatus known in the art employs a non-volatile memory mounted on a replaceable unit for the purpose of improving the image quality of a copier or printer, or other device, and in order to perform accurate management of the lifetime of the replaceable unit. In an image forming apparatus of this kind, the connection between the non-volatile memory of the replaceable unit and the apparatus proper is achieved by a connector. However, since the signal to the non-volatile memory is very weak, a malfunction can occur even if there is only a slight imperfection in electrical contact within the connector.
Accordingly, in an effort to avoid faulty contact in the connector, an image forming apparatus in which a main body of the apparatus proper and the non-volatile memory are coupled electromagnetically has been proposed in the specification of Japanese Patent Application Laid-Open No. 11-338329.
More specifically, in a printer that employs an electrophotographic process, for example, a process cartridge (replaceable unit), which is obtained by integrating a photosensitive drum, a developing device and a toner accommodating compartment, or other device, is removably installed in the printer and is equipped with a non-contact IC memory unit for recording such information as the history of use and the process conditions, or other data.
In a case where information is recorded in the IC memory unit or information in the IC memory unit is updated, specified information is merely recorded in a designated memory area and, as a consequence, there is the possibility that items of related data will no longer be in conformity with each other. Accordingly, the IC memory unit is so arranged that items of data that are interrelated are rewritten automatically when information serving as the reference is recorded. Among these items of interrelated information, the information serving as the reference is referred to as higher-order information and the information that is rewritten in association with the higher-order information is referred to as lower-order information.
Consider a case where information (denoted by xe2x80x9cNewCartridgeBitxe2x80x9d below) indicating a cartridge that is brand new and information (denoted by xe2x80x9cFirstInstallDatexe2x80x9d below) indicating first date of use is registered in the IC memory unit. In this instance, the former is higher-order information and the latter is lower-order information. If the cartridge is a new cartridge, a NewCartridgeBit is set in the mounted IC memory unit and a date serving merely as an initial value is recorded as the FirstInstallDate.
If printing is executed upon installing the new cartridge in the printer, the NewCartridgeBit constituting the higher-order information is reset and, in association therewith, the date of print execution is recorded as the FirstInstallDate, which is the lower-order information. However, a printer control unit within the printer does not possess data indicative of the current date. In actuality, therefore, the FirstInstallDate is recorded in response to receipt of current-date data possessed by a controller that has been connected to the printer or by an external host computer that has been connected to the printer via this controller.
However, in a conventional printer in which the cartridge having the built-in memory is installed, the items of information that have been recorded in the memory of the cartridge will not necessarily be in harmony with each other.
For example, the above-mentioned printer often possesses a test-print function that enables the printing function to be checked in the development stage of the printer without connecting a controller that assists in data communication with, e.g., an external host computer.
When test printing is performed in the above-mentioned conventional printer, a new (unused) cartridge is installed in the printer. However, because a controller or host computer has not been connected to the printer, data indicative of the current date cannot be acquired in the printer control unit and, as a consequence, the FirstInstallDate cannot be recorded in the IC memory unit of the cartridge, and the NewCartridgeBit is merely reset.
The problem that arises in this case is that even if a controller is connected and printing is performed after the test print, the fact that the NewCartridgeBit will already have been reset means that nothing will be recorded for the FirstInstallDate, which is the lower-order information updated in association with the NewCartridgeBit.
Thus, if only the higher-order information of interrelated information within the IC memory unit of the above-described conventional printer is updated or if the lower-order information is not capable of being updated for some reason, then it will not be possible to subsequently update only the related lower-order information. Thus, the problem arises that the information that is recorded in the memory unit will be defective.
Accordingly, an object of the present invention is to provide an image forming apparatus, in which a cartridge with a built-in memory is installed, and a method of controlling the memory, wherein the apparatus is capable of maintaining the conformity between mutually related information that has been recorded in the memory within the cartridge.
In order to attain the above-described objects, an image forming apparatus of the present invention comprises a structure as follows.
An image forming apparatus from which a unit having a non-volatile memory for storing first and second information can be removed, comprises: update designation means for designating the updating of information stored in the non-volatile memory; and update means for updating the information, which has been recorded in the non-volatile memory, based upon a designation by the update designation means; wherein the update means updates the second information after the completion of updating of the first information in a case where the designation is to update the first information, and the update means updates the second information if the second information is a predetermined value, in a case where the designation is to update the second information.
In order to attain the above-described objects, a memory control method of the present invention comprises the steps as follows.
A memory control method in an image forming apparatus from which a unit having a non-volatile memory for storing first and second information can be removed, comprises: an update designation step of designating the updating of information stored in the nonvolatile memory; a first update step of updating the second information after a completion of updating of the first information in a case where it is designated to update the first information at the update designation step; and a second update step of updating the second information if the second information is a predetermined value, in a case where it is designated to update the second information at the update designation step.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.